1. Field of the Invention
The present invention relates to a scroll compressor, and more particularly, to an abrasion resistance structure of a scroll compressor, which is capable of preventing abrasion between a orbiting scroll and a main frame, which is caused by the thermal deformation of the orbiting scroll during the operation of the compressor.
2. Description of the Background Art
In general, a compressor for converting mechanical energy into latent energy of a compressible fluid is divided into a reciprocating compressor, a scroll compressor, a centrifugal compressor, and a vane compressor.
The scroll compressor sucks up and compresses a gas using a solid of revolution and discharges the compressed gas like the centrifugal compressor or the vane compressor unlike the reciprocating compressor.
FIG. 1 is a vertical sectional view showing an example of a conventional scroll compressor.
As shown in FIG. 1, the conventional scroll compressor includes a casing 1 including a suction pipe (SP) and a discharge pipe (DP), a main frame 2 and a sub frame 3 respectively fixed to the upper and the lower sides of the inner circumference of the casing 1, a driving motor 4 including a stator 4A and a rotor 4B loaded between the main frame 2 and the sub frame 3, a driving shaft 5 press fitted to the center of the rotor 4B of the driving motor 4 and penetrating the main frame 2, the driving shaft 5 for transmitting the rotary power of the driving motor 4, a orbiting scroll 6 combined with the driving shaft 5 and put on the upper surface of the main frame 2, a fixed scroll 7 combined with the orbiting scroll 5 and fixed to the upper surface of the main frame 2 so as to form a plurality of compression pockets, a high-pressure-low-pressure dividing plate 8 combined with the back surface of the fixed scroll 7, the high-pressure-low-pressure dividing plate 8 for dividing the inside of the casing 1 into a suction pressure region and a discharge pressure region, and a non-return valve assembly 9 combined with the back surface of the fixed scroll 7, the non-return valve assembly 9 for preventing the reverse flow of the discharged gas.
The main frame 2 has a flat upper surface so that the upper surface forms a thrust bearing surface together with the back surface of an end plate 6b of the orbiting scroll 6. The end plate 6b of the orbiting scroll 6, which faces the main frame 2, is flat like the upper surface of the main frame 2.
Wraps 6a and 7a forming an involute curve are formed between the opposite surfaces of the orbiting scroll 6 and the fixed scroll 7 so that the orbiting scroll 6 and the driving motor 4 can form the plurality of compression pockets while the orbiting scroll 6 and the driving motor 4 are geared with each other and continuously move when the orbiting scroll 6 receives the rotary power of the driving motor 4, to thus be in an orbiting motion.
In FIG. 1, a reference numeral 5a denotes an oil channel.
The operation of the conventional scroll compressor will now be described.
When power is applied to the stator 4A of the driving motor 4, the rotor 4B rotates together with the driving shaft 5 inside the stator 4A and the orbiting scroll 6 orbits by an eccentric distance. The wrap 6a of the orbiting scroll 6 forms the plurality of compression pockets between the wrap 7a of the fixed scroll 7. The volumes of the compression pockets are reduced while the compression pockets move toward the center of the scrolls due to the continuous orbiting motion of the orbiting scroll 6. Accordingly, the compression pockets suck up and compress refrigerant gas and discharge the compressed refrigerant gas.
However, in the above-mentioned conventional scroll compressor, since the pressures of the compression pockets positioned in the center of the scrolls 6 and 7 are highest, thermal deformation occurs in the centers of the scrolls due to a rise in temperature according to the increase of the pressure as the compressor continues compression stroke. The thermal deformation causes the orbiting scroll 6 to hang down to the direction of gravity.
At this time, the orbiting scroll 6 forms the thrust bearing surface in a state where the back surface of the end plate 6b contacts the upper surface of the main frame 2. However, the main frame 2 and the orbiting scroll 6 press each other since the orbiting scroll 6 locally hangs down due to the thermal deformation of the centers of the scrolls. The back surface of the end plate 6b and the upper surface of the main frame 2 are abraded more than the outside of the end plate. Accordingly, noise is generated and the orbiting scroll 6 unstably operates.
Therefore, an object of the present invention is to provide an abrasion resistance structure of a scroll compressor, which is capable of preventing the back surface of the end plate of an orbiting scroll and the upper surface of a main frame facing the back surface of the end plate from being locally abraded due to the thermal deformation of the orbiting scroll during compression stroke.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided an abrasion resistance structure of a scroll compressor, comprising a casing comprising a suction pipe (SP) and a discharge pipe (DP), a main frame and a sub frame respectively fixed to the upper and lower sides of the inner circumference of the casing, a driving motor comprising a stator and a rotor loaded between the main frame and the sub frame, a driving shaft press fitted to the center of the rotor of the driving motor and penetrating the main frame, the driving shaft for transmitting the rotary power of the driving motor, an orbiting scroll combined with the driving shaft, put on the upper surface of the main frame, and having a concavely inclined portion on the back surface of an end plate of the orbiting scroll, a fixed scroll combined with the orbiting scroll and fixed to the upper surface of the main frame so as to form a plurality of compression pockets, and a non-return valve assembly combined with the back surface of the fixed scroll, the non-return valve for preventing the reverse flow of a discharged gas.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.